| 摘要 |
PROBLEM TO BE SOLVED: To provide an inlet duct in which a ventilation resistance at an inside part of a bent part is reduced.SOLUTION: An inlet duct 11 has an inlet, an outlet and a bent part. A distance (an inner diameter L) between points 18, 19 where a virtual plane P including a flow passage central line of the inlet duct 11 having the bent part and a section M acting as a section of the bent part is equal to a diameter of a circular section N acting as a section other than that of the bent part. A pair of areas 20, 21 becoming inside of the bent part protrude more outward in a radial direction than that of the circular section N. An inner wall part 16 forms a curved surface with a lower curvature factor than that of an arc of the circular section N. A pair of areas 22, 23 becoming an outer side of the bent part are placed more inside in a radial direction than from the circular section N. A size of the inner diameter L and a flow passage sectional area along the virtual plane P are kept constant over the entire inlet duct 11 and in turn, as a distribution of the passage sectional area at the section M, it is enlarged more in an inside area of the bent part and it is shrunk more at the outside area of the bent part as compared with that of the circular section N. |
